Conventionally, pressure switches that output, for example, on and off signals based on fluid pressure have been widely used. Such pressure switches include those installed and used at sites where the pressure of a fluid containing a corrosive chemical, such as high-purity nitric acid, hydrochloric acid, or hydrofluoric acid, is measured, as in, for example, semiconductor manufacturing processes. As a concrete example, a semiconductor manufacturing apparatus uses a chemical solution containing hydrofluoric acid for etching semiconductor substrates. To stably supply the chemical solution, a pressure switch is installed in a circulation circuit for the chemical solution.
Because the above chemical solution is highly corrosive, a pressure switch having superior chemical resistance (chemical solution resistance) is required for installation in such a corrosive environment. Hence, the above semiconductor manufacturing apparatus uses a pressure switch in which a member formed of a resin having chemical resistance is disposed at a site where the switch comes into contact with the chemical solution.
The pressure switch can output on and off signals, for example, by a known mechanical switching method using a spring (for example, see Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2001-266721